FreeBSD and busybox only support "I" as the flag, not "i". GNU sed actually supports both "i" and "I". However, since FreeBSD only supports "I", I propose that one. Note that one sed tutorial (http://www.grymoire.com/Unix/Sed.html#uh-38) [^] only notes "I" with GNU sed, so that seems to be the more popular choice. Note, however, that perl uses "i" not "I" - so there is some argument for "i". If people want to use "i" as the flag instead of "I" that's fine with me. We just need to pick a flag so sed scripts can port.